Ancient measuring tools chase points! ! !

Sima Qian wrote in "Zhong You" that when Dayu was in charge of water conservancy, there was such a passage: "(Yu) took a bus by land, a boat by water and a sled by mud. Ride out on the mountain, left, right, and carry four lines to open Kyushu and Tongjiu Road. " Here, Sima Qian showed us a vivid picture, and Yu led the investigation team to control water. You see, with surveyors and measuring instruments on your shoulders, you have all the accuracy, rope, ruler and moment. They sometimes travel by car on land, sometimes take boats on water, sometimes sit on wooden sleds in muddy swamps, and sometimes climb mountains with shoes with nails. It can be seen that "accuracy, rules and moments" are measuring tools used in ancient times.

"Quasi" is a level used in ancient times. This is recorded in Hanshu. "Rope" is a tool for measuring distance, drawing straight lines and leveling, and it is one of the earliest tools for length measurement and leveling. Yu's "Left Criterion" in water control is to measure the height of the terrain with "accuracy" and "rope" and compare the difference between the heights. The instrument is a tool to correct the circle. Moment is an ancient tool for drawing squares, that is, a square ruler. The ancients summarized various surveying and mapping functions of moments, which can not only determine elevation, measure height, measure depth and measure distance, but also draw circles and squares. A simple "moment" can be used to measure the height, distance and size of an object because it is placed in different positions. Its widespread use embodies the infinite wisdom of ancient people in China.

However, "accuracy, rope, gauge and moment" is not the earliest measuring tool. 1952, people found a clan village site about 67,000 years ago in banpo village, Xi City, Shaanxi Province. In this site, there are complete residential areas, including 46 round or square houses, all of which face south. From this, it can be concluded that travelers can accurately identify the direction. How do they tell the direction? Presumably, they observe the sun and stars to tell the direction.

General objects, such as trees and houses, will produce shadows in the sun. People often observe these shadows in production and life practice. Slowly, people found that these shadows not only changed with time, but also changed regularly. "Immediate Effect" is an ancient surveying work by China. The ancients used "immediate effect" to set the direction, determine the time, or determine the length of solar terms or even the year of return, and so on. It can be said that the oldest and simplest measuring tool in China is "table", that is, ordinary bamboo poles, wooden poles or stone pillars. People have studied the "polar shadow" for thousands of years. After long-term production practice, people have created a set of "the skill of measuring lofty" through the calculation and deduction of "extreme shadow", and "immediate effect" has become an idiom in Chinese.